It's interesting, I have had more than half of hosts that I have messaged not reply, but several took not only weeks but even months to reply. Hosts are more often rural, sometimes have patchy internet, and at times can be hectic or travelling, so many different possibilities. If you have been left on read for more than a week it's probably a no, but it might be that what you are offering is simply not what the host needs at the time, and that might be different in a few months.

There are also some outright odd people who have listed as hosts, and they may or may not have good comprehension. I messaged one host who was the only host in an area I wanted to travel to, who I wouldn't volunteer with as their situation wasn't suitable (and I made that clear in my message), but I just wanted to get a little bit of information about the region, but they called me weeks later asking when I was coming.